Field
The disclosed concept relates generally to electrical switching apparatus such as, for example, circuit breakers. The disclosed concept also relates to harness assemblies for electrical switching apparatus.
Background Information
Electrical switching apparatus are used to protect electrical circuitry from damage due to a trip condition, such as, for example, an overcurrent condition, an overload condition, an undervoltage condition, a relatively high level short circuit or fault condition, a ground fault or arc fault condition. Molded case circuit breakers, for example, include at least one pair of separable contacts which are operated either manually by way of a handle located on the outside of the case, or automatically by way of a trip unit in response to the trip condition. Some molded case circuit breakers have wires that attach to internal components and exit the circuit breaker for use with external systems. In order for the circuit breaker to be properly certified, such as, for example and without limitation, to be properly certified by Underwriters Laboratories Inc., headquartered in Northbrook, Ill., the wiring configuration must pass a pull test. The pull test generally involves disconnecting the wires from the internal components and applying a pull force (e.g., ten pounds) to each of the wires separately external the circuit breaker for one minute. During the test, there can be no displacement within the wire routing.
A known solution that attempts to satisfy the pull test involves extending the wires through a sleeve member (e.g., without limitation, a heat shrink tube) and clamping the sleeve member with a blocking member. One problem with this solution is that many circuit breakers do not have adequate space to accommodate a blocking member. Furthermore, requiring a blocking member for each bundle of wires within the circuit breaker undesirably increases the cost of the circuit breaker, and also complicates its manufacture.
There is, therefore, room for improvement in electrical switching apparatus and harness assemblies therefor.